In product development, 30% to 40% of a manufacturer's parts are duplicates or have acceptable substitutes to parts already created, according to a study by the Aberdeen Group. Aberdeen goes on to say that there is an annual carrying cost of between $4,500 and $23,000 per item for the introduction of new parts where there was an acceptable duplicate part available. That said, tools that allow manufacturer's the ability to search for existing parts substantially reduce product development with part reuse. Traditionally, those tools were text-based descriptions of the part geometry, but limits for those tools were soon reached as products began to include more and more complicated parts. Another limitation also occurs in cases when working in a multi-lingual environment when translation among various languages may break-down the accuracy of the text-based part description.
A recent trend in data management of product development moves from searching the above mentioned text-based descriptors to, instead, searching the geometry of the parts themselves. This is a difficult problem that requires highly technical solutions. A difficulty here is that the user may want the geometry of a part to be considered unchanged when that part is translated, rotated, or even sometimes scaled.
One common solution to the above problem consists in extracting a descriptor from the geometries that is itself invariant under translation, rotation or scaling and to then use these descriptors to index the geometries. Invariance means that the same result is returned no matter the orientation of the sketch. Scale invariance implies invariance with respect to scaling by a factor, only. Same with translation and rotation invariance. One reason behind the success of such a solution lies in the fact that it efficiently divides the work in two phases: (1) an off-line phase where the extraction of the descriptor from the geometry is a relatively slow process, but one that needs to be performed only once; and (2) an on-line phase, where the comparison of descriptors is a very fast process that allows quick retrieval of similar geometries. These common solutions compare the silhouettes of two-dimensional (“2D”) objects in order to determine their external similarity.
What is needed is a system, process, and method for determining a rotation invariant sketch descriptor that includes not only the external similarities, but also the internal similarities that is often times as important.